/*
 * Copyright (c) 2019 Spotify AB.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.spotify.heroic.metadata

import com.fasterxml.jackson.annotation.JsonIgnore
import com.spotify.heroic.cluster.ClusterShard
import com.spotify.heroic.common.DateRange
import com.spotify.heroic.common.Features
import com.spotify.heroic.common.OptionalLimit
import com.spotify.heroic.common.Series
import com.spotify.heroic.filter.Filter
import com.spotify.heroic.metric.FullQuery
import com.spotify.heroic.metric.RequestError
import com.spotify.heroic.metric.ShardError
import eu.toolchain.async.Collector
import eu.toolchain.async.Transform

data class FindSeries(
    val errors: List<RequestError> = listOf(),
    val series: Set<Series> = setOf(),
    val limited: Boolean = false
) {
    constructor(series: Set<Series>, limited: Boolean): this(listOf(), series, limited)

    companion object {
        @JvmStatic fun reduce(limit: OptionalLimit): Collector<FindSeries, FindSeries> {
            return Collector { results: Collection<FindSeries> ->
                val errors = mutableListOf<RequestError>()
                val series = mutableSetOf<Series>()
                var limited = false

                results.forEach {
                    errors.addAll(it.errors)
                    series.addAll(it.series)
                    limited = limited || it.limited
                }

                FindSeries(
                    errors,
                    limit.limitSet(series),
                    limited || limit.isGreater(series.size.toLong())
                )
            }
        }

        @JvmStatic fun shardError(shard: ClusterShard): Transform<Throwable, FindSeries> {
            return Transform { e: Throwable ->
                FindSeries(errors = listOf(ShardError.fromThrowable(shard, e)))
            }
        }
    }

    @JsonIgnore
    fun isEmpty(): Boolean = series.isEmpty()

    data class Request(
        val filter: Filter,
        val range: DateRange,
        val limit: OptionalLimit,
        val features: Features
    ) {
        companion object {
            @JvmStatic
            fun withLimit(request: FullQuery.Request, limit: OptionalLimit): Request {
                return Request(request.filter(), request.range(), limit, request.features())
            }
        }
    }
}